The embodiments described herein relate to mechanisms for routing cables, more specifically to medical devices, and still more specifically to endoscopic tools. More particularly, the embodiments described herein relate control cable routing in surgical instruments for teleoperated medical devices.
Known techniques for Minimally Invasive Surgery (MIS) employ instruments to manipulate tissue that can be either manually controlled or controlled via computer-assisted teleoperation. Many known MIS instruments include a therapeutic or diagnostic end effector (e.g., forceps, a cutting tool, or a cauterizing tool) mounted on a wrist mechanism at the distal end of an extension (also referred to herein as the main tube or shaft). The wrist mechanism may provide one or more orientation, translation, or combinations of orientation and translation degrees of freedom for the end effector. The end effector often has one or more additional mechanical degrees of freedom, such as a scissors or grip degree of freedom. In some instances, the wrist and end effector degrees of freedom may be combined in a single mechanism, such as a combined yaw and grip degree of freedom.
To enable the desired movement of the wrist mechanism and end effector, known instruments include tension members (e.g., cables, tension bands) that extend through the main tube of the instrument and that connect the wrist mechanism to a transmission or actuator (also referred to herein as a backend mechanism). The backend mechanism moves the cables to operate the wrist mechanism. For robotic or teleoperated systems, the backend mechanism is motor driven and can provide mechanical force or torque input to the backend, and this force or torque is transmitted to one or more cables in order to operate the wrist or end effector degrees of freedom.
Known backend systems employ one or more pulleys to route the control cables from the backend mechanism and into the shaft. Although known arrangements reduce friction associated with cable movement and bends, the use of pulleys and shafts increases cost, complexity, and assembly time. Thus, a need exists for mechanism for routing tension members between the proximal end (i.e., the backend mechanism) and the distal end (i.e., the wrist mechanism) of medical instruments. A need also exists for improved cable routing mechanisms having reduced size, reduced part count, lower cost of materials, and which permit easy assembly including installation of tension members.